Question

Name the antibiotic used in the Lederberg's replica plating experiment.

• A. Neomycin
• B. Penicillin
• C. Streptomycin
• D. Both B and C

Answer 1

The correct option is D Both B and C

Joshua Lederberg and Esther Lederberg in 1952 conducted experiments to demonstrate the genetic basis of the drug-resistant mutation in the bacteria Escherichia coli. They used the techniques of replica plating. From a culture of Escherichia coli derived from a single cell, they spread cells onto a "master" agar plate. Each cell gave rise to a distinct colony. They then placed a velvet cloth to the replica plate and touched it to a new plate. In the same spatial relationship as the colonies from which they had been taken a few colonies appeared on the replica plate, having grown from Penicillin resistant mutant cells.

When all the colonies on the master plate were tested for penicillin resistance, only those colonies that had been the source of penicillin-resistant cells on the replica plate displayed resistance.

This experiment indicates that some bacterial cells had acquired drug-resistant mutation even before they were exposed to penicillin.

Similarly, this experiment is also used to detect streptomycin resistant mutants

Hence , both streptomycin and penicillin can be used in replica plating experiment.

So, the correct answer is D.